Résumé:
The experimental work has focused on evaluating the antioxidant activity of
methanol extracts of Rosmarinus officinalis prepared from dried rosemary leaves
collected from three different sites in the region of Sebdou station (Sidi el Djilali) in the
wilaya of Tlemcen and one site in the region Messerghine (forest of Madagh) in the
wilaya of Oran. Soil samples for analysis were also randomly taken from the place of
harvest of the species studied.
Analysis of plant extracts by thin layer chromatography (TLC) revealed a wealth
of Rosmarinus officinalis in flavonoids including flavones luteolin-type and glucosides
derivatives, confirming the results of the determination of polyphenols by the Folin
Ciocalteu method and those of the flavonoids by method of Lamaison and Carnat.
Quantitative evaluation of total polyphenols and flavonoids that shows that the
four plant extracts are relatively rich in polyphenols with values ranging between 36
and 40 mg GAE / g of extract and flavonoids with values ranging from 7 to 11 mg QE/
g of extract. The antiradical power estimate of four different plants extracts vis-à-vis the
radical DPPH confirm that the extracts are very active with IC50 (DPPH) values that
fluctuate between 0.03 and 0.04 mg / ml. The antioxidant activity was also determined
by the test of reducing power of méthanolics extracts by the method of Oyaizu who
could demonstrate that the Rosmarinus officinalis also has the ability to reduce free
radicals by converting them into stable and inactive molecule.
Finally, measurement of the TBA index also called index of lipid peroxidation in
minced beef incorporated a single dose of 1000 ppm extract of Rosmarinus officinalis and
kept for one week at 2 ° C was given after the eighth Updated significant results of 0.52
mg MDA / kg meat treated with rosemary extract against 0.79 mg MDA / kg in the
control sample. From the results obtained in this work, we can say that the species
Rosmarinus officinalis is really with a powerful antioxidant and can effectively
substitute for synthetic antioxidants, the results of sensory test were done confirm these
data.
